Re: [Proposal] Make the optimiser aware of partitions ordering

On Thu, Sep 21, 2017 at 11:13 AM, Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:
> On Thu, Sep 21, 2017 at 10:52 AM, Ashutosh Bapat
> <ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
>> With 9140cf8269b0c4ae002b2748d93979d535891311, we store the
>> RelOptInfos of partitions in the RelOptInfo of partitioned table. For
>> range partitioned table without default partition, they are arranged
>> in the ascending order of partition bounds. This patch may avoid
>> MergeAppend if the sort keys match partition keys by creating an
>> Append path by picking sorted paths from partition RelOptInfos in
>> order. You may use slightly modified version of
>> add_paths_to_append_rel().
>
>
> Yes, I just saw this commit this morning, and this is exactly what I
> was missing, thanks for the pointer and the patch!

PFA v3 of the patch, once again rebased and that now use all the newly
available infrastructure.

I also added a check that a sorted append can't be generated when a
default partition has been declared.